[PATCH v3 3/9] ACPI/IORT: Check ATS capability in root complex nodes

Jean-Philippe Brucker
2019-04-17T18:28:19Z

Root complex node in IORT has a bit telling whether it supports ATS or
not. Store this bit in the IOMMU fwspec when setting up a device, so it
can be accessed later by an IOMMU driver. In the future we'll probably
want to store this bit at the host bridge or SMMU rather than in each
endpoint.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
---
drivers/acpi/arm64/iort.c | 11 +++++++++++
include/linux/iommu.h | 4 ++++
2 files changed, 15 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index e48894e002ba..4000902e57f0 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1028,6 +1028,14 @@ void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
dev_dbg(dev, "dma_pfn_offset(%#08llx)\n", offset);
}

+static bool iort_pci_rc_supports_ats(struct acpi_iort_node *node)
+{
+ struct acpi_iort_root_complex *pci_rc;
+
+ pci_rc = (struct acpi_iort_root_complex *)node->node_data;
+ return pci_rc->ats_attribute & ACPI_IORT_ATS_SUPPORTED;
+}
+
/**
* iort_iommu_configure - Set-up IOMMU configuration for a device.
*
@@ -1063,6 +1071,9 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
info.node = node;
err = pci_for_each_dma_alias(to_pci_dev(dev),
iort_pci_iommu_init, &info);
+
+ if (!err && iort_pci_rc_supports_ats(node))
+ dev->iommu_fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
} else {
int i = 0;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 480921dfbadf..51ab006d348e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -446,6 +446,7 @@ struct iommu_fwspec {
const struct iommu_ops *ops;
struct fwnode_handle *iommu_fwnode;
void *iommu_priv;
+ u32 flags;
unsigned int num_ids;
u32 ids[1];
};
@@ -458,6 +459,9 @@ struct iommu_sva {
const struct iommu_sva_ops *ops;
};

+/* ATS is supported */
+#define IOMMU_FWSPEC_PCI_RC_ATS (1 << 0)
+
int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
const struct iommu_ops *ops);
void iommu_fwspec_free(struct device *dev);
--
2.21.0